Many modern flight control systems rely on various air data parameters, such as dynamic pressure, to calculate aircraft control commands. It is thus undesirable for the flight control system to receive inaccurate air data signals. Typically, dynamic pressure is sensed using one or more pitot tubes. Most often, a pitot tube is located on the wing or front section of an aircraft, with its opening facing forward. As aircraft airspeed varies, ram air pressure at the pitot tube opening also varies. The pressure variations can thus be used to determine and indicate aircraft airspeed.
Because the pitot tube opening faces forward, it can become blocked. The sources of potential blockage are numerous and varied, and include ice, water, volcanic ash, dirt, insects, and various other contaminants. A blocked pitot tube can cause inaccurately sensed dynamic pressure and thus, for example, inaccurate aircraft airspeed being determined and displayed. Presently, there are no back-up dynamic pressure sensors beyond the use of redundant pitot tubes, which are also susceptible to blockage. This blockage can occur on a single sensor or as a result of a common mode event such as, for example, icing or volcanic ash. In the unlikely, but possible, event of multiple pitot probe blockages or contaminations, it would be possible for valid, yet erroneous data to be used by the control laws or displayed to the flight crew.
Hence, there is a need for a system and method for determining aircraft dynamic pressure that is not susceptible to blockage by debris and various other sources. The present invention addresses at least this need.